Dirty knives sealed fate of St Kilda people

Infant deaths that forced the population of St Kilda to abandon their archipelago resulted from infected umbilical cords

The catastrophic infant death toll that forced islanders to abandon St Kilda was caused by toxic bacteria carried on contaminated knives used to sever the umbilical cords of new-born babies, says a new study.

Between 1830 and 1890, 88 babies survived less than 28 days on St Kilda - accounting for about 60% of the infants born on the island. The community became unsustainable and the last islanders left in 1930.

It is widely accepted that the babies died from tetanus, which is caused by a bacterium found in soil and animal manure. The bug releases spores which infect wounds and release a neurotoxin that attacks the nervous system.

For decades it was believed that the infection was spread by midwives daubing the umbilical cords of new-born babies with contaminated seabird oil. The theory was disproved in 2004 when analysis of fulmar oil - which was also used by the islanders for